Assembly aid for machine parts, in particular for housing closure units

ABSTRACT

The invention refers to an auxiliary assembly element for automatic mounting of machine parts, such as housing sealing covers for combustion engines, where the auxiliary assembly element, which may be attached to the machine part and easily removed, receives the mounting devices for the connection of the machine parts with the machine into supports where they are position-oriented and arrested, so that the mounting devices, together with the machine part, may be supplied to and moved directly into the connection position with the machine via the auxiliary assembly element with the use of an industrial robot or similar.

BACKGROUND OF THE INVENTION

This invention refers to an auxiliary assembly element for machine partswhich have to be connected with the machine with the aid of additionalmounting devices, consisting of an auxiliary element which may beattached to and easily removed from the machine part, and which may beremoved after the assembly is completed. This invention concernsparticularly an auxiliary assembly for housing sealing covers withintegrated radial shaft sealing ring and through holes for mountingscrews, particularly for crank shafts, cam shafts, and gear housings ofcombustion engines, consisting of a base element which extendsessentially radially with at least one axially extending ring-shapedprojection for the concentric accommodation of the housing sealingcover.

In order to mount machine parts it is required that the machine part tobe mounted is moved to the machine in true position and is thenconnected with it. The connection of such machine parts often occurs byusing mostly standardized mounting elements, such as rivets, screws,clamp pins, etc. While in the construction of large machinery, theassembly of machine parts takes place mostly manually, possibly with thehelp of special holding tools, where the mounting tools after assemblyare moved into their mounting position individually and most of the timeby hand, the mass production of machine housings, such as electricmotors, combustion engines, control gears, etc., presents specialrequirements for the possibility of automatic mounting.

In the construction of motor vehicles in particular, the housing sealingcovers, for instance, which have to be mounted with several screws onthe motor or gear housing, are moved to the mounting location and alsopositioned there and screw connected, with automatic tools, such asindustrial robots. This requires that the housing sealing covers may beremoved from storage in position-oriented position and may betransported to the motor or gear housing, resp., while the mountingscrews should also be transported in true position together with thehousing sealing cover, if possible.

In DE-PS DE 42 17 131 a housing sealing cover for a crank shaft housingfor combustion engines is described, in which the mounting screws arekept friction-locked in the screw through-holes of the housing sealingcover so that when the housing sealing cover is moved to be attached tothe crank shaft housing the mounting screws are automatically also movedinto the screw position. While the screws for the mounting of thehousing sealing cover are directly available, the friction-lockedconnection of the screws in the bore holes of the housing sealing coveris problematic, however, as is the necessary positioning of the screwsin the direction of the threaded holes of the machine housing during themounting process. In addition, the housing sealing covers which areequipped with such screws cannot be stacked and are therefore notsuitable for automatic pick-up by industrial robots.

Finally in housing sealing covers with a shaft extending through thecover in the assembly stage, which require additional sealing, theautomatic mounting is made more difficult because the sealing lip of theradial shaft sealing ring integrated in the housing sealing cover mustbe radially expanded when the cover is moved onto the motor shaft.

In addition, an auxiliary assembly element is known from EP-PS 0 272 775which is designed to make the mounting of a housing sealing cover withintegrated radial shaft sealing ring easier. The auxiliary assemblyelement consists essentially of a base element of plastic materialswhich extends radially and with a radial cylindrical shell fastened onthe inside to support the sealing lip of the radial shaft sealing ring,especially to push the housing cover with its sealing ring onto the endof the shaft. In addition, the auxiliary assembly element has a radialouter second axial ring-shaped cylinder projection, which encloses acorresponding recess of the housing sealing cover and thereby ensures acentric position of the sealing lip of the radial shaft sealing ring.The housing sealing cover is attached in assembled condition with thecrank shaft housing of a combustion engine via several screws. Themounting screws have to be supplied separately after positioning andalignment of the housing sealing cover.

The invention is based on the task to simplify the assembly of machineparts which are connected via additional mounting devices with themachine housing, and primarily to permit fully automatic mounting byindustrial robot. This includes safe transport and storage of suchmachine parts.

This task is accomplished in accordance with the invention by anauxiliary assembly element, which is equipped with supports for aposition-oriented accommodation and arresting of the mounting devices.The use of an auxiliary assembly element does increase the productioncosts of the machine parts because an auxiliary assembly element must bemade available and connected with the machine part. The possibility ofmultiple use of such auxiliary assembly elements, however, keeps theseadditional costs limited. The big technical and economic advantage isthat the mounting devices for the machine part are held by the auxiliarymounting element in such a position that, after moving the machine partinto the assembly position, the mounting devices are available in trueposition and may be moved into their functional mounting position.

Preferably the auxiliary assembly element consists of a plastic elementwhich may be produced with a spray process simply and inexpensively in aform which is adjusted to the machine apart. Such an auxiliary assemblyelement has a low weight and may be used multiple times.

The auxiliary assembly preferably consists of a base element extendingin the primary level of the machine part from which projections protrudewhich enclose the machine part and/or reach into the machine part, andwhich may be connected to and easily removed from the machine part. Aplug-in connection is usually sufficient and easily managed.

In addition, it is suggested that supports in the form of through-holesare provided in the auxiliary assembly element for the mounting devicesinto which the mounting devices may be moved and positioned so that theymay be inserted. This ensures that the mounting devices may be picked upduring assembly by a common tool and may be moved through the auxiliaryassembly element into the connection position with the machine housing.

In order to prevent the loss of a mounting device during transport andstorage, it is suggested that the through-holes in the auxiliaryassembly element are equipped with arresting aids so that the mountingdevices may be accommodated and removed. In addition, it appears to beadvantageous if the through-holes have additional guiding aids for thepositioning during transport and storage as well as for the supply ofthe mounting devices into the machine part in true position duringassembly.

In addition, it is suggested that the extension of the auxiliaryassembly element corresponds approximately to the length of the mountingdevices. This ensures that the mounting devices do not project from theauxiliary assembly element during transport and storage. This permitsthat the auxiliary assembly elements with the machine parts may bestacked. This is particularly significant when the auxiliary assemblyelement including machine part is picked up by an industrial robot.

In the known auxiliary assembly elements of plastic materials forhousing sealing covers with integrated radial shaft sealing ring andthrough-holes for mounting screws, particularly for crank shaft, camshaft, and gear housings of combustion engines, consisting of anessentially radially extending base element with at least one axiallyextending ring-shaped projection for concentric accommodation of thehousing sealing cover, it is suggested that the auxiliary assemblyelement is equipped with supports to accommodate and position themounting screws so that they are position-oriented. According to theinvention the known auxiliary assembly elements for housing sealingcovers are improved to the extent that the mounting screws may bereceived by the auxiliary assembly element in true position and are heldin this position during transport and storage up to the time ofassembly, in order to be screwed directly through the housing cover holeinto the threaded hole of the crank shaft or gear housing, resp., byusing a common tool. Preferably a collar in the radial outercircumference of the auxiliary assembly element which is axially angledis provided during assembly as support against the crank shaft housing.This is advantageous when the mounting screws are pressed axially out ofthe supports of the auxiliary assembly element into the threaded holesof the crank shaft housing.

An additional design of the invention provides that the support toaccommodate one mounting device consists of one each essentially axiallypositioned, radially elastic extendable projection with a through-holefor one mounting screw. When the mounting screw is moved into thethrough-hole, the projection expands radially elastically and holds itafter the projection has sprung back.

According to an additional characteristic of the invention, theprojection may be made elastic resilient by axially running slots orsimilar. This results in tongue-shaped projections. Preferably eachsupport consists of at least three tongue-shaped, essentially axiallyaligned projections. The latter preferably have recesses to house andarrest the screw head. These recesses are designed such that the head ofthe mounting screws may be pressed in and out.

Advantageously, mounting screws with parts which project radially beyondthe screw head, such as protuberances, flanges, shoulders, or similar,are used while the radially projecting parts, such as the shoulder of ashoulder head screw, may be pressed in and out of the recesses.

In addition, the design of the axially aligned projections isadvantageous with extensions, which extend in the direction of the screwshanks. This ensures a centric support of the mounting screw shanks, andthe screws are held in exactly aligned position so that during assemblythe screws are held centric to the threaded holes of the crank shaft orgear housing, resp., in the auxiliary assembly element.

In addition, the invention suggests that in the auxiliary assemblyelement centering lugs are provided which extend axially beyond thepicked-up machine part or the picked-up housing sealing cover, resp., inthe direction of the machine housing, and which during assembly,particularly when the parts to be mounted are joined, permit that theparts are arranged position-oriented to each other. It is notsignificant whether the centering lugs reach into corresponding cut-outsin the machine housing or whether the centering lugs orient themselveson projecting edges of the machine housing during assembly. For a clearpositioning or centering, resp., of the parts at least two centeringlugs should be provided on the auxiliary assembly element.

Finally, it seems appropriate to attach arresting clamps on theauxiliary assembly element for a correctly positioned connection withthe machine part or with the housing sealing cover, resp., where severalarresting clamps increase the precision in regard to positioning.Centering lugs and arresting clamps may be combined such that thecentering lug is part of the arresting clamp.

DESCRIPTION OF THE DRAWINGS

A design example of the invention is shown in the drawing and isdescribed in more detail below.

Shown are:

FIG. 1 a view of a housing sealing cover for the crank shaft exit of acrank shaft housing on the gear side of a combustion engine,

FIG. 2 a cut I—I of the housing cover according to FIG. 1,

FIG. 3 a view of an auxiliary assembly element for the housing sealingcover shown in FIG. 1 and FIG. 2,

FIG. 4 a cut II—II of the auxiliary assembly element according to FIG.3,

FIG. 5 a view of the auxiliary assembly element according to FIG. 3 andFIG. 4 with attached housing sealing cover according to FIG. 1 and FIG.2,

FIG. 6 a cut III—III according to the information in FIG. 5,

FIG. 7 an enlarged cut of detail A according to the information in FIG.6 during assembly,

FIG. 8 detail A according to FIG. 6 after assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The housing sealing cover shown in FIG. 1 and FIG. 2 consists of adeep-drawn metal element with a radial flange 2, which, in mountedcondition, rests on the crank shaft housing 26 of a combustion engine(see FIG. 8). For a static seal a seal bulge 3 of elastomer material isprovided. In the radial inner area of the housing sealing cover 1 aradial shaft sealing ring 4 of elastomer material is attached, which isequipped with two sealing lips 5 and 6, which during assembly rest onthe surface of the crank shaft 29 (see FIG. 8) under radial tension. Theaccommodation of the radial shaft sealing ring 4 takes place on a collar7 of a cylindrical recess 8. Mounting screws 22 designed as shoulderhead screws which may be inserted through the bore holes 9, are providedto mount the housing sealing cover 1 on the crank shaft housing 26 (SeeFIG. 7 and FIG. 8).

For the automatic assembly of the housing sealing cover 1 an auxiliaryassembly element 10 of a polyamide plastic material is provided, asshown in FIG. 3 and FIG. 4. The auxiliary assembly element 10 consistsof a base element 11, which essentially extends radially and is equippedradially inside with an axially aligned projection 12 in the form of acylindrical shell for the radial support of the sealing lips 5 and 6 ofthe housing sealing cover 1 (see FIG. 2) during transport and storage aswell as for simplified mounting on the crank shaft 29. A second, alsocylindrical, axially aligned projection 13 is designed for the auxiliaryassembly element 10 to be attached and to centrically held on the recess8 of the housing sealing cover 1. According to the location of themounting screws 22 the auxiliary assembly element 10 is equipped withsupports 14 which consist of three each tongue-shaped, essentiallyaxially aligned projections 15. The latter have slot-shaped recesses 16as arresting aids to house the shoulder 23 of the mounting screws 22(see FIG. 7). In addition, the projections 15 are equipped with axialextensions 17, serving as guiding aids, and extending in the directionof the screw shanks 24 (see FIG. 7). The auxiliary assembly element 10additionally has two axial projecting centering lugs 18, which arearranged in the direction of the housing sealing cover 1, and which arepart of two arresting clamps 19. On the outer circumference 20 of theauxiliary assembly element 10 an axially angled collar 21 is provided asadditional support.

FIGS. 5 through 7 show the auxiliary assembly element 10 which isattached on the housing sealing cover 1. The axial projection of theauxiliary assembly element 10 encloses the cylindrical recess 8 of thehousing sealing cover 1, while the shell-shaped axial projection 12 ofthe auxiliary assembly element 10 extends into the radial shaft sealingring 4 of the housing sealing cover 1 with simultaneous radial expansionof the sealing lips 5 and 6. In addition, the auxiliary assembly element10 with its two arresting clamps 19 is attached on axially projectingcollar parts 20′ and 20″ of the housing sealing cover 1, while thecentering lug 18 of the auxiliary assembly element 10 results in a clearalignment and position-securing of the housing sealing cover 1 to theauxiliary assembly element 10.

The connection element consisting of auxiliary assembly element 10 andhousing sealing cover 1 may be stacked position-oriented and maytherefore be transported, stored, picked up by an industrial robot, andmoved into mounting position without a problem.

The detail A, shown enlarged in FIG. 7, shows in particular the support14 for the mounting screws 22 which are held arrested with their collar23 in the recesses 16 of the tongue-shaped projections 15 after axialsupply. The screw shanks 24 of the mounting screws 22 are alignedexactly via the extensions 17 so that they, when the housing sealingcover 1 is mounted, are positioned precisely in front of the threadedholes 25 of the crank shaft housing 26 (FIG. 8) and may be easilyscrewed in. Screwing in the mounting screws 22 takes place with commontools 27, which are only indicated in the drawing, and which, whenplaced on the screw head 28, simultaneously expand the tongue-shapedprojections 15 radially outward, thereby freeing the collar 23 of themounting screws 22, so that the screw shank s 24 of mounting screws 22may be screwed into the threaded holes 25 of the crank shaft housing 26.

The advantages of the invention shown in this design example may beapplied in principle to many machine parts which require additionalmounting devices in order to be mounted. For instance, it may concernsimple seal covers of gear housings; it is also feasible to equip valvecovers and oil pans of combustion engines with the auxiliary assemblyelements according to the invention by the valve cover or oil panmanufacturer, resp., in order to achieve the above mentioned advantagesduring transport, storage and especially during fully automaticassembly.

Those skilled in the art will recognize that a particular application ofthe inventive concept is using the form of positioning element describedto aid in positioning a rear crankshaft seal assembly adjacent a planarend face on an engine block. The seal assembly is preferably of the typethat includes an elastomeric seal body forming a part of a largercarrier unit. The carrier unit has a radial flange, a static seal orgasket formed in the flange, and a generally cylindrical pocket oroffset portion defined by an axial section and a radial flange to whichthe seal body is bonded.

The positioning element not only carries the fasteners in aligned orregistered position relative to the carrier, but also engages both theouter circumference of the offset portion axial flange and the seal bandon the inside diameter of the elastomeric seal body. For this latterpurpose, a short axial sleeve or collar that slides over the OD of thecrankshaft end is provided. After the combination seal and carrier areinstalled on the engine, the positioning element is removed and theelastomeric seal lip slides off the sleeve and engages the crankshaft inits intended operating position. This prevents distorting the seal lipas the seal is initially positioned over the end of the crankshaft.

It will thus be seen that the present invention provides a novelauxiliary assembly element having a number of advantages andcharacteristics, including those pointed out herein and other which areinherent in the invention. Preferred methods and apparatus have beenshown by way of example, it is anticipated that modifications andvariations to the described form of the invention will occur to thoseskilled in the art, and it is anticipated that such variations ormodifications may be made without departing from the spirit of theinvention or the scope of the appended claim.

I claim:
 1. A fastener holding device capable of repeated use,comprising, in combination, a body with an axially extending flangehaving a working clearance fit over a first part associated in use withsaid flange, a second axially extending flange adapted to hold a surfaceof a second part to be fastened in place on a machine housing by aplurality of fasteners, said body holding said flanges in fixed relationto each other, and a third element adapted to retain a plurality offastener-receiving fingers, each fastener-receiving finger beingflexibly attached to said body, said fastener-receiving fingerscomprising at least three generally axially extending legs and a pocketfor each leg, said pocket being adapted to grasp the enlarged headportion of said fastener and transiently prevent movement of saidfastener in both axial directions thereof, said pockets and said axiallegs deflecting sufficiently to allow said fasteners to be pressed intofastener-receiving openings in said machine housing when said fasteneris engaged with a fastener driver and axial force is applied to saidfastener driver, said legs of said fastener-holding device beingdeflectable so as to permit said fastener to engage said machinehousing, and release the engagement of said fasteners with said holdingdevice.
 2. A fastener holding device as defined in claim 1, wherein saiddevice is made of a plastic material.
 3. A fastener holding device asdefined in claim 2, wherein said plastic is a flexible thermoplasticmaterial which may deflect repeatedly without damage to it.
 4. Afastener holding device as defined in claim 1, wherein said body isgenerally in the form of a ring.
 5. A fastener holding device as definedin claim 1, wherein said first part is a portion attached to thecrankshaft of an auto or truck by a slip fit, concentric connection. 6.A fastener holding device as defined in claim 1, wherein said fastenersand said device have an approximately equal axial extent.
 7. A fastenerholding device as defined in claim 1, wherein said first flange is alsoadapted to hold the lip portion of a seal away from the crankshaft withwhich it is to be associated in use, said lip seal thereby engaging saidcrankshaft portion by the innate resiliency of the lip seal when thedevice holding it spaced from the crankshaft is withdrawn.
 8. A fastenerholding device as defined in claim 1, wherein said body is adapted tohold a seal assembly for a combustion engine, said second axiallyextending flange snugly but removably engaging said axial flange portionof an oil seal.
 9. A fastener holding device as defined in claim 1, saiddevice including at least one arresting clamp positionable inregistration with said machine part whereby to aid in the aligning ofthe machine part and the sealing cover.
 10. A fastener holding device asdefined in claim 9, wherein said at least one arresting clamp includes acentering lug.
 11. A fastener holding device as defined in claim 1,wherein the device is intended to mate with an engine housing whichincludes a third axial flange portion that registers with a portion ofsaid engine to insure correct alignment of said fastener holding device.